How to get host name with port from a http or https request

Question

I have two applications deployed in jboss container same unix box   If i get a request from app1  i need to frame a corresponding request for app2   eg  if app1 request is  http   example com context param1 123 then I need to extract  http   example com    so that I can frame request for second app   I tried using     HttpServletRequest getServerName    amp     HttpServletRequest getServerPort    amp      HttpServletRequest getHeader  host      methods  but the request may be of http or https   Please let me know if there is any other better way  Thanks

User · Answer

You can use HttpServletRequest getRequestURL and HttpServletRequest getRequestURI   StringBuffer url   request getRequestURL    String uri   request getRequestURI    int idx      uri    null   amp  amp   uri length    gt  0     url indexOf uri    url length     String host   url substring 0  idx     base url idx   host indexOf         if idx  gt  0      host   host substring idx     remove scheme if present

User · Answer

If your server is running behind a proxy server  make sure your proxy header is set   proxy set header X-Forwarded-Proto   scheme    Then to get the right scheme  amp  url you can use springframework s classes   public String getUrl HttpServletRequest request        HttpRequest httpRequest   new ServletServerHttpRequest request       UriComponents uriComponents   UriComponentsBuilder fromHttpRequest httpRequest  build         String scheme   uriComponents getScheme                   http   https     String serverName   request getServerName           hostname com     int serverPort   request getServerPort              80     String contextPath   request getContextPath          app         Reconstruct original requesting URL     StringBuilder url   new StringBuilder        url append scheme  append             url append serverName        if  serverPort    80  amp  amp  serverPort    443            url append      append serverPort             url append contextPath       return url toString

User · Answer

I m late to the party  but I had this same issue working with Java 8   This is what worked for me  on the HttpServletRequest request object   request getHeader  origin      and   request getHeader  referer      How I came to that conclusion   I have a java app running on http   localhost 3000 making a Http Post to another java app I have running on http   localhost 8080   From the Java code running on http   localhost 8080 I couldn t get the http   localhost 3000 from the HttpServletRequest using the answers above   For me using the getHeader method with the correct string input worked   request getHeader  origin   gave me  http   localhost 3000  which is what I wanted   request getHeader  referer   gave me  http   localhost 3000 xxxx  where xxxx is full URL I have from the requesting app

User · Answer

If you use the load balancer  amp  Nginx  config them without modify code   Nginx   proxy set header       Host  host    proxy set header  X-Real-IP   remote addr    proxy set header  X-Forwarded-For  proxy add x forwarded for    proxy set header X-Forwarded-Proto   scheme      Tomcat s server xml Engine    lt Valve className  org apache catalina valves RemoteIpValve    remoteIpHeader  X-Forwarded-For    protocolHeader  X-Forwarded-Proto    protocolHeaderHttpsValue  https   gt     If only modify Nginx config file  the java code should be   String XForwardedProto   request getHeader  X-Forwarded-Proto

User · Answer

Seems like you need to strip the URL from the URL  so you can do it in a following way   request getRequestURL   toString   replace request getRequestURI

User · Answer

If you want the original URL just use the method as described by jthalborn  If you want to rebuild the url do like David Levesque explained  here is a code snippet for it   final javax servlet http HttpServletRequest req    javax servlet http HttpServletRequest       final int serverPort   req getServerPort    if   serverPort    80      serverPort    443          No need to add the server port for standard HTTP and HTTPS ports  the scheme will help determine it    url   String format   s    s       req getScheme    req getServerName            else     url   String format   s    s  s      req getScheme    req getServerName    serverPort            You still need to consider the case of a reverse-proxy    request getScheme   is returning http instead of returning https in java   Could use constants for the ports but not sure if there is a reliable source for them  default ports    Are HTTP and HTTPS default port numbers defined in the JDK    Most developers will know about port 80 and 443 anyways  so constants are not that helpful   Also see this similar post

User · Answer

You can use HttpServletRequest getScheme   to retrieve either  http  or  https    Using it along with HttpServletRequest getServerName   should be enough to rebuild the portion of the URL you need   You don t need to explicitly put the port in the URL if you re using the standard ones  80 for http and 443 for https    Edit  If your servlet container is behind a reverse proxy or load balancer that terminates the SSL  it s a bit trickier because the requests are forwarded to the servlet container as plain http  You have a few options   1  Use HttpServletRequest getHeader  x-forwarded-proto   instead  this only works if your load balancer sets the header correctly  Apache should afaik    2  Configure a RemoteIpValve in JBoss Tomcat that will make getScheme   work as expected  Again  this will only work if the load balancer sets the correct headers   3  If the above don t work  you could configure two different connectors in Tomcat JBoss  one for http and one for https  as described in this article

[java] How to get host name with port from a http or https request

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